Field of the Invention
The present invention relates to a multi-piece solid golf ball having at least a five-layer construction that includes a two-layer core, an envelope layer, an intermediate layer and a cover layer. The invention relates in particular to a multi-piece solid golf ball capable of delivering overall a ball performance which is fully acceptable to professional golfers and skilled amateur golfers.
Prior Art
Various golf balls have hitherto been developed for professional golfers and skilled amateurs. Of these, from the standpoint of achieving both a superior distance performance in the high head-speed range and good controllability on shots with an iron and on approach shots, multi-piece solid golf balls having an optimized hardness relationship among the layers encasing the core, such as the intermediate layer and the cover layer, are in widespread use. Moreover, because not only the flight performance, but also the feel of the ball at impact and the spin rate of the ball after being struck by a club have a large influence on control of the ball, one important topic in golf ball development is optimizing the thicknesses and hardnesses of the golf ball layers in order to achieve the best possible feel and spin rate. Furthermore, there exists a desire for the ball to have durability to repeated impact and for scuffing observed on the ball surface when a golf ball is repeatedly hit with different clubs to be suppressed (increased scuff resistance), maximal protection of the ball from external factors also being an important topic in golf ball development.
Such golf balls that have appeared in the art include the golf ball having a three-layer cover and a two-layer core described in U.S. Pat. No. 7,625,302. In addition, golf balls having a three-layer cover and a one-layer core are described in U.S. Pat. Nos. 8,523,707, 8,771,103, 7,335,115, 7,918,749 and 8,764,584.
Also, U.S. Pat. No. 6,913,547 discloses a golf ball having a two-layer cover and a two-layer core, and JP No. 4017228 describes a golf ball having a two-layer core and a one-layer cover.
However, these prior-art golf balls, in spite of possessing multilayer structures of the sort described above, have not yet achieved an adequately reduced spin rate on shots with a driver. Hence, there exists a desire for the development of a golf ball which can provide the further increase in distance expected by professionals and skilled amateurs. Moreover, in terms of golf ball performance, there is also a desire for the ball to have a good controllability on approach shots, to have the ability to move forward on a straight path particularly on full shots, to have a good scuff resistance, and to be fully acceptable to professional golfers and skilled amateurs.
It is therefore an object of the invention to provide a multi-layer solid golf ball which, along with satisfying at a very high level the flight and control performances expected for use by professional golfers and skilled amateurs, has the ability to move forward on a straight path, particularly on full shots, and also has an excellent scuff resistance.